Diabetes mellitus is a chronic disease, which occurs when the pancreas does not produce enough insulin (Type I), or when the body cannot effectively use the insulin it produces (Type II). This condition typically leads to an increased concentration of glucose in the blood (hyperglycemia), which can cause an array of physiological derangements (e.g., kidney failure, skin ulcers, or bleeding into the vitreous of the eye) associated with the deterioration of small blood vessels. Or, a hypoglycemic reaction (low blood sugar) is induced by an inadvertent overdose of insulin, or after a normal dose of insulin or glucose-lowering agent accompanied by extraordinary exercise or insufficient food intake.
A variety of transcutaneous sensor devices have been developed for continuously measuring blood glucose concentrations. Typically, these types of sensor devices employ an applicator or other similar insertion tool for inserting a transcutaneous sensor under a host's skin. Conventionally, the applicator comprises a plunger and a needle formed with a lumen configured to receive the sensor. Because of the additional parts (e.g., an applicator with a plunger) and steps (e.g., a sensor unit retraction step) required for sensor deployment, use of a separate applicator or other similar tools for sensor insertion can be cumbersome, or difficult, particularly for a new user.